This invention relates to the treatment of kidney disease in diabetic and non-diabetic patients. More specifically, the invention relates to a system for treating kidney disease in diabetic and non-diabetic patients with Chronic Intermittent Intravenous Insulin Therapy.
Diabetic kidney disease (nephropathy) develops in 35 to 40% of patients with type 1 diabetes mellitus (DM) and in 10 to 60% of patients with type 2 DM depending upon the ethnic pool being studied. It is the most common cause of End-Stage Renal Disease (ESRD) in the United States. Experts generally have assumed that diabetic nephropathy is the result of hyperglycemia, whether alone or in combination with other factors, such as hypertension and genetic susceptibility to kidney disease. Two major recent clinical trials involving patients with type 1 DM (Diabetes Control and Complication Trial [DCCT]) and type 2 DM (United Kingdom Prospective Diabetes Study [UKPDS]) have demonstrated that improved glycemic control reduces the onset and the progression of early diabetic nephropathy to overt nephropathy in patients recently diagnosed with diabetes mellitus (DM) thereby giving additional credence to the hypothesis that a lack of glycemic control is the primary cause. Both of theses studies used recently diagnosed patients some of whom, although well controlled, went on to develop kidney disease. Since the DCCT and UKPDS studies demonstrated that near normalization of blood glucose level did not always result in a delay of the onset or progression of diabetic nephropathy, the hypothesis that euglycemia is the means for addressing this disease, is made suspect.
Once nephropathy has become clinically overt (that is, macroalbuminuria and decreased glomerular filtration rate are detected), the degree of glycemic control is shown to have lost its importance as a factor. This observation provides additional evidence to refute the claim that glycemic control is the primary factor to be addressed in kidney disease, and that other mechanisms have greater overall influence. Indeed, most patients with DM and proteinuria eventually will progress to ESRD or premature death from cardiovascular complications. In such patients, with no medical intervention, the glomerular filtration rate decreases an average of 1 ml/min per month, a deterioration that leads to ESRD in a mean period of 7 years. Once overt persistent proteinuria is established, no known strategy exists that can stop or reverse the progression to ESRD. Appropriate antihypertensive therapy has been shown to significantly reduce renal and possibly cardiovascular mortality in proteinuric type 1 DM patients, as well as retard the rate of decline of glomerular filtration rate in some patients with impaired renal function (Lewis A J et al, N Engl J Med 1993,329:1456-62). Thus, the standard of care for patients with diabetic nephropathy is intensive glycemic control and normalization of the blood pressure using primarily angiotensin converting enzyme inhibitors.
The pathophysiology of diabetic nephropathy is only partially understood. The most consistent morphologic finding in diabetic nephropathy is the enlargement of the mesangium, which can compress the glomerular capillaries and thus alter intraglomerular hemodynamics. McLennan et al (Diabetes, 1994,43:1041-45) showed that a high glucose concentration inhibits degradation of the mesangium and could promote the mesangial enlargement observed in diabetic nephropathy.
The inventor hypothesizes that an improvement in the entire metabolic milieu as observed with Chronic Intermittent Intravenous Insulin Therapy (CIIIT) could reverse the process discussed above and have favorable effects on the progression of overt diabetic nephropathy. Furthermore, Chronic Intermittent Intravenous Insulin Therapy has been shown to improve blood pressure control substantially and to reduce by 46% the antihypertensive medication requirements in patients with type 1 DM (Aoki T T et al, Diabetes Care, 1995,18:1260-65), possibly through an improvement in vascular reactivity. This effect was hypothesized by the inventor to favorably influence the intraglomerular hemodynamics and delay the progression of diabetes-related renal disease.
What is needed is a system that improves the entire metabolic process and through its multiplicity of effects on neurovascular reactivity, intraglomerular pressure and hemodynamics, could arrest the progression of overt diabetic nephropathy, improve intraglomerular hemodynamics, and thus arrest the progression of diabetic nephropathy and therefore reduce the risk of development of ESRD.
Accordingly, the present invention is a system capable of improving the entire metabolic process and through its multiplicity of effects on neurovascular reactivity, intraglomerular pressure and hemodynamics, arresting the progression of overt diabetic nephropathy, improving intraglomerular hemodynamics, and thus arresting the progression of diabetic nephropathy and therefore reducing the risk of development of ESRD. The current invention is the treating of kidney disease using insulin pulses to a patient utilizing Chronic Intermittent Intravenous Insulin Therapy to achieve the slowing, stopping or reversing of kidney disease in both diabetic and non-diabetic patients.
One preferred embodiment of the invention is a system for treating kidney disease in diabetic and non-diabetic patients through an intravenous administration of a pulse of insulin comprises a means for determining a respiratory quotient of a patient, a liquid or food containing glucose, an intravenous site, and a means of delivering a pulse of insulin at a regular interval of time.
In the preferred embodiment of the treatment system, any instrument capable of measuring the respiratory quotient determines a respiratory quotient of a patient. The respiratory quotient is defined as the ratio of carbon dioxide produced to oxygen consumed by the patient. In the preferred embodiment, a liquid or food containing glucose is consumed by the patient to prevent hypoglycemia. The preferred liquid or food containing glucose is GLUCOLA, however any similar liquid or food containing glucose that will prevent hypoglycemia in the patient may be used.
The preferred means of delivering insulin is an infusion device. It is preferable that the infusion device is capable of providing pulses of insulin on a prearranged interval, so long as there is sufficient glucose in the blood to keep the patient from becoming hypoglycemic. The preferred infusion device is also capable of delivering the pulses of insulin in as short duration of time as possible, without adversely affecting the vein at the site of infusion is used. However, less accurate devices may deliver the pulses and achieve the needed infusion profile.
In the preferred embodiment, the intravenous site is a temporary or permanent IV access site located in the body, forearm or hand of the patient. The amount of insulin is tailored to achieve more normal metabolic function of the kidney. Metabolic function is measured as stabilization or decrease in 24-hour urinary protein excretion or stabilization or increase in creatinine clearance. Type 1 diabetic patients receive 20-35 milliunits of insulin per kilogram of body weight per pulse and type 2 diabetic patients receive 70-200 milliunits of insulin per kilogram of body weight per pulse. During periods of non-use, the IV site is preferably converted to a heparin or saline lock.
In one embodiment of the method of the invention, the patient is seated in a blood drawing chair and a 23 gauge needle/catheter is inserted into a hand or forearm vein to obtain vascular access. Although a 23 gauge needle catheter is preferred, any system of such access may accomplish the needed result, including indwelling catheters. After a short equilibration period, usually thirty minutes, the respiratory quotient (the ratio of carbon dioxide produced to oxygen consumed by the patient) of the patient is measured. The respiratory quotient measuring device may be any presently known model manufactured by any presently known supplier of such instruments. In the preferred embodiment, the patient is then asked to drink or eat liquid or food containing glucose usually on the order of 60 to 100 grams of glucose. In the preferred embodiment a pulse of insulin is administered intravenously on a regular interval of time, usually every six minutes, until the respiratory quotient (RQ) shows improvement, as indicated by a respiratory quotient of 0.90 or greater. In the preferred embodiment, improvement in RQ is generally achieved within one hour. In the preferred embodiment, the insulin/oral glucose phase is then followed by a rest period of usually one hour. In the preferred embodiment the entire procedure repeated until the desired effect is achieved.
The preferred method of insulin pulse delivery would be a prearranged interval, so long as there is sufficient glucose in the blood to keep the patient from becoming hypoglycemic. In order to determine the progress of the patient, it is preferable the RQ is measured every hour and blood glucose levels are checked every 30 minutes. The blood glucose level may be measured by any means which shows that the patient is not becoming hypoglycemic. In the preferred embodiment, the patient is free to move around after the initial insulin pulses have been administered. In the preferred embodiment, the intravenous site is converted to a heparin or saline lock. The patient returns to the blood drawing chair to receive their next series of insulin pulses. In the preferred embodiment, the subsequent insulin pulses must be covered by supplying glucose by mouth or other means. The total time of the preferred procedure is approximately 6-7 hours.
In the preferred embodiment, two successive days of three treatments are performed with a new patient. In the preferred embodiment, the above is repeated once a week. For patients who need a more intensive approach, it is preferable the procedure be repeated 3 or more times, including continuously each week until the desired clinical outcome is achieved.
In the non-diabetic patient more glucose may be required than in the diabetic patient, but the other parameters would remain the same, including the need for a pulse delivery.